Hair thickening and conditioning gelatin composition for topical application

ABSTRACT

Hair thickening compositions for topical applications containing an aqueous gelatin solution having a concentration between about 0.30 and about 15% by weight and further including a water-soluble cosmetic film-forming polymer at a concentration greater than 30% of that of the gelatin and between about 0.10 and about 15% by weight, and an acid neutralizing agent to maintain said solution at a pH range between about 6.0 and about 9.5 at which the gelatin and film-forming polymer are stable together in aqueous solution at their respective concentrations. Methods for preparing stable aqueous solutions containing gelatin and a water-soluble film-forming polymer are also disclosed, as well as methods for increasing hair shaft thickness by topical application of the inventive hair thickening compositions to the hair.

BACKGROUND OF THE INVENTION

The present invention relates to hair thickening and conditioningcompositions, and in particular to aqueous gelatin solutions, theapplication of which to the hair results in a significant increase inhair shaft thickness. The present invention also relates to methods forpreparing the gelatin compositions of the present invention, as well asto methods for increasing hair shaft thickness by topical application tothe hair of the gelatin compositions of the present invention.

U.S. Pat. No. 4,749,684 discloses that the ingestion of gelatin promotesan increase in the linear growth rate of hair. Scala et al., Nutr. Rep.Int., 13(6), 579-92 (1976) discloses that dietary supplementation withgelatin produces an increase in hair thickness. The ability to increasehair thickness by the topical application of gelatin is unreported.

Hair coated with gelatin is difficult to comb in the absence of aconditioning agent, but stable solutions of gelatin with a conditioningagent have been heretofore unknown. Lindo et al., "Hair Processing andConditioning," Hum. Hair Sym. [Pap.], 1st, (Brown, Editor, MEDCOM Press,New York 1974 (Meeting Date 1973)) pages 135-44 reports the capabilityof hair to absorb topically applied hydrolyzed gelatin, but with littlesubstantivity, so that little gelatin remains after thorough washingwith room temperature water.

U.S. Pat. No. 4,208,402 discloses a topical solution for improving theappearance of oily hair or skin, including the scalp, containing fromabout 0.5 to 1.5% by weight of gelatin and from 0.15 to 0.45% by weightof partially hydrolyzed polyvinyl acetate in aqueous or hydroalcoholicsolution. The level of film-forming polymer disclosed is insufficient toprovide a readily combable product. By the manufacturing processdisclosed, aqueous solutions cannot be formed with higher concentrationsof the film-forming polymer without the gelatin precipitating from thesolution.

Topical application of gelatin to hair would be possible if stableaqueous solutions containing higher concentrations of film-formingpolymers could be prepared. The inability to comb hair to which gelatinsolutions have been topically applied has prevented the recognition thattopical gelatin application increases hair shaft thickness.

There remains a need for stable aqueous gelatin solutions containinghigher levels of film-forming polymer to provide gelatin solutions fortopical hair application that do not resist combing.

SUMMARY OF THE INVENTION

This need is met by the present invention. It has now been discoveredthat stable aqueous gelatin solutions can be prepared with levels offilm-forming polymer greater than or equal to that of the gelatin bycarefully maintaining an essentially neutral solution pH, whiledissolving the gelatin and the film-forming polymer together. It hasfurther been discovered that the topical application of such gelatinsolutions to the hair leaves the hair easy to comb and produces asignificant increase in hair shaft thickness, as confirmed byindependent laboratory testing.

Therefore, in accordance with the present invention, a hair thickeningcomposition for topical application is disclosed in the form of anaqueous gelatin solution having a concentration between about 0.30 andabout 15% by weight and further including a water-soluble cosmeticfilm-forming polymer at a concentration greater than 30% that of thegelatin and between about 0.10 and about 15% by weight, wherein thesolution is within a pH range at which the gelatin and the film-formingpolymer are stable together in aqueous solution at their respectiveconcentrations.

The present invention also provides a method for preparing stableaqueous solutions containing gelatin and a water-soluble cosmeticfilm-forming polymer. In accordance with this aspect of the presentinvention, a method for preparing a stable aqueous solution of gelatinand a water-soluble cosmetic film-forming polymer is disclosed, whichmethod includes the steps of:

dissolving up to about 30% by weight of gelatin in a first quantity ofwater, so that an aqueous gelatin solution concentrate is formed;

dissolving up to about 30% by weight of a water-soluble cosmeticfilm-forming polymer in a second quantity of water, while maintainingthe solution pH between about 6.0 and about 9.5 as the polymer is addedto the second quantity of water, so that an aqueous polymer solution isformed; and

mixing the aqueous gelatin solution concentrate with the polymersolution while maintaining the solution pH between about 6.0 and about9.5. so that a stable aqueous solution of gelatin and polymer is formed.

By carefully maintaining the solution pH between about 6.0 and about9.5. it is possible to form solutions containing elevated concentrationsof gelatin and water-soluble cosmetic film-forming polymers. Suchpolymer concentrations provide a product that conditions and detanglesthe hair, while at the same time providing a significant increase inhair shaft thickness. As an added benefit, applied product may have itsholding ability reactivated by simply applying a fine mist of water tore-moisten the hair, giving it the ability to be re-set by combing orbrushing into place again.

As will be readily appreciated, the method of the present invention maybe utilized to prepare a product concentrate that may be diluted with asolvent selected from water and cosmetically acceptable alcohols toobtain the hair thickening compositions of the present invention.Methods in accordance with the present invention may therefore furtherinclude the step of diluting the stable aqueous solution of gelatin andpolymer with a solvent selected from water and cosmetically acceptablealcohols so that an aqueous solution containing between about 0.30 andabout 15% by weight of gelatin and a water-soluble cosmetic film-formingpolymer at a concentration greater than 30% that of the gelatin andbetween about 0.10 and about 15% by weight.

Thus, it will be appreciated that concentrates capable of being dilutedto form the hair thickening compositions of the present invention arealso included within the scope of the present invention. Concentrates inaccordance with the present invention have a viscosity between about4,000 and about 400,000 cps. at room temperature and a polymer togelatin ratio between about 10:3 and about 50:1.

The foregoing method makes possible for the first time the preparationof aqueous solutions containing water-soluble film-forming polymerconcentrations greater than 30% of the gelatin concentration. This, inturn, led to the discovery of the beneficial hair shaft thickeningeffects resulting from the topical application of gelatin to the hair.Therefore, in accordance with another aspect of the present invention, amethod for increasing hair shaft thickness is disclosed, which methodtopically applies in an amount sufficient to impregnate the hair anaqueous solution of gelatin at a solution concentration between about0.30 and about 15% by weight and a water-soluble cosmetic film-formingpolymer at a solution concentration greater than 30% that of the gelatinand between about 0.10 and about 15% by weight, wherein the solution iswithin a pH range at which the gelatin and the film-forming polymer arestable together at their respective concentrations.

The solution preparation method of the present invention may be utilizedto prepare hair thickening compositions in a variety of forms suitablefor topical application to the hair. The hair thickening compositions ofthe present invention may be in the form of gels, lotions, creams,mousses, tonics, hair dyes, coloring agents and aerosol orpump-dispensed hair setting sprays and hair conditioning products. Thecompositions of the present invention are particularly versatilebecause, in addition to thickening the hair shaft, the compositionsprovide a hardening, or "setting," effect upon application that softenswith combing without diminishing the hair shaft thickening effect. Thus,individuals seeking a hair "setting" effect would simply apply thecomposition and set the hair, while individuals preferring a softer,natural feel, would simply comb or brush the hair after the product isapplied and set. Hair can be re-set by simply applying a water mist andallowing the hair to dry.

The gelatin solutions of the present invention, by containing elevatedlevels of film-forming polymer, and the inventive methods by which suchsolutions are prepared, possess novelty independent of the hairthickening effect provided by the topical application of the solutionsto the hair. Thus, the compositions of the present invention, and themethods by which they are prepared, may be used to prepare essentiallyany aqueous composition for topical application to the skin, hair orscalp containing elevated levels of gelatin and film-forming polymer. Infact, the compositions of the present invention and the methods by whichthey are prepared may be employed with essentially any end-useapplication that would benefit from the combination of gelatin with afilm-forming polymer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides aqueous gelatin solutions thatsignificantly increase hair shaft thickness upon topical application tothe hair. Unlike prior art gelatin-based hair treatment compositions,the compositions of the present invention contain levels ofwater-soluble cosmetic film-forming polymers that leave the hair easy tocomb following topical application of the product. Until now, it was notpossible to prepare gelatin solutions containing levels of film-formingpolymers disclosed herein.

Essentially any commercially available gelatin suitable for use incosmetic products may be used for the hair thickening compositions ofthe present invention. This would include Type A gelatin derived frompork skin and ranging in molecular weight or viscosity from 50 to 300bloom, and Type B gelatin prepared from calf skin or bone and ranging inmolecular weight or viscosity between 50 and 300 bloom. Type A 250 bloomgelatin is preferred. However, essentially any amino acid solution orcolloid equivalent to gelatin may be used in the composition of thepresent invention.

The hair thickening compositions of the present invention will containbetween about 0.30% and about 15% by weight of gelatin, and preferablybetween about 1 and about 5% by weight of gelatin. A gelatinconcentration of 1.3% is most preferred.

Essentially any water-soluble cosmetic film-forming polymer is suitablefor use with the hair thickening compositions of the present invention.Representative polymers include polyvinyl pyrrolidone (PVP), polyvinylacetate, partially hydrolyzed polyvinyl acetate, copolymers of PVP andvinyl acetate, polyvinyl alcohol, acrylate-acrylamide copolymers,acrylate-PVP copolymers, and the like. Suitable polymers have anumber-average molecular weight ranging between about 5,000 and 100,000daltons, and preferably fall within a molecular weight range betweenabout 10,000 and about 50,000 daltons.

The preferred water-soluble cosmetic film-forming polymer is PVP.Cosmetic-grade PVP is available from BASF under the brand designationLUVISCOL. The grade of LUVISCOL having a molecular weight of about45,000 daltons is most preferred. The equivalent grade of PVPmanufactured by ISP of Linden, N.J. is also suitable.

The quantity of polymer to be employed, as will the quantity of gelatin,will vary depending upon the molecular weight and the desired viscosityof the final product. In addition, the level of polymer employed shouldbe that amount sufficient to leave the hair easy to comb followingtopical application of the composition of the present invention. Thatamount is greater than 30% of the gelatin concentration, and in fact mayexceed the gelatin concentration, and ranges between about 0.10 andabout 15% by weight. A polymer concentration between about 2.5 and about7.5% by weight is preferred, provided that the concentration of polymeris greater than 30% that of the gelatin. A polymer concentration ofabout 5.6% is most preferred.

To promote the hair thickening effect of the compositions of the presentinvention, the concentration of polymer is preferably greater than 60%that of the gelatin, and even more preferably is greater than 90% thatof the gelatin. Most preferably, the amount of polymer exceeds that ofthe gelatin.

Suitable hair thickening compositions in accordance with the presentinvention will range in viscosity between about 500 and about 80,000cps. measured at 25° C. Viscosities between about 2,000 and 55,000 cps.are preferred, while a viscosity ranging between about 35,000 and 45,000cps. is most preferred.

Depending upon the choice of gelatin and polymer molecular weight, itmay be necessary to add a thickening agent to the composition of thepresent invention in order to obtain the desired viscosity. Preferredthickening agents include the CARBOPOL series of polyacrylic acid andcross-linked polyacrylic acid thickening agents available from B. F.Goodrich. CARBOPOL 941 is particularly preferred. Other suitablethickening agents include modified starches, vegetable gums and otherconventional thickening agents suitable for cosmetic use.

Hair thickening compositions in accordance with the present inventiontypically contain between about 0% and about 5.0% by weight ofthickening agent. A thickening agent level between about 0.2% and about0.5% by weight is preferred, while a thickening agent level of 0.3% byweight is most preferred.

Water-soluble cosmetic film-forming polymers such as PVP lower the pH ofaqueous solutions in which they are dissolved, thereby reducing thesolubility of gelatin therein. Gelatin likewise reduces the pH ofaqueous solutions in which it is dissolved, so that as the amount ofgelatin dissolved in an aqueous solution increases, the amount ofadditional gelatin that can be further dissolved in that solutionsignificantly decreases. This effect is even more pronounced when apH-lowering film-forming polymer such as PVP is dissolved in solution.

Therefore, in order for aqueous solutions of gelatin and polymers suchas PVP to remain stable at the concentrations disclosed by the presentinvention, the pH of the solutions must be maintained above a pH atwhich the gelatin and polymer do not precipitate out of solution,typically above about 6.5 for PVP, although this will vary somewhat forother polymers.

For purposes of the present invention, a composition is considered"stable" if it is consistently capable of being stored at about roomtemperature for at least about two weeks without separation orprecipitation of individual components. Indefinite stability is, ofcourse, ideal. The minimum pH at which a given polymer will becompatible with gelatin can be readily determined by one of ordinaryskill in the art without undue experimentation.

The solution pH should also be maintained below the pH at which thegelatin and polymer precipitate out of solution. Polymers such as PVPremain stable with gelatin up to a pH of about 8.5. Higher pH's may beemployed with a sacrifice of long-term stability. The PVP-basedcompositions of the present invention possess indefinite stability at apH between about 6.9 and about 7.5.

To maintain the pH within this range, an acid neutralizing agent isadded to the film-forming polymer-containing gelatin solutions of thepresent invention while the solutions are being prepared, typically, byfirst dissolving the film-forming polymer with the addition of an acidneutralizing agent to maintain the pH within the required range whilethe polymer is being dissolved. A gelatin concentrate is then added tothe polymer solution with further addition of the acid neutralizingagent to maintain the pH within the required range.

Essentially any acid neutralizing agent suitable for use with cosmeticproducts may be used. Examples of suitable acid neutralizing agentsinclude triethanol amine (TEA), which is preferably added in the form ofa 99% solution, sodium hydroxide, and the like. TEA is most preferred.

The amount of acid neutralizing agent added to the hair thickeningcompositions of the present invention will depend upon the amount of pHdrop caused by the gelatin and film-forming polymer, which will in turndepend upon the amount of each ingredient used and the lot to lotvariation in acidity. However, compositions in accordance with thepresent invention will typically contain less than 2% by weight of TEA,and will more typically contain about 0.5% by weight of TEA.

The hair thickening compositions of the present invention may optionallyinclude up to about 5% by weight of a preservative that functions as ananti-bacterial agent and/or an antioxidant. Methylparaben is a preferredantioxidant because it functions as both an anti-bacterial agent and anantioxidant. The compositions of the present invention may also beperfumed and/or colored for purposes of appearance, if desired. Inaddition, the compositions may optionally include conventional levels ofa hair dye or hair coloring agent. Conventional levels of well-knownUV-absorbing sunscreening agents may also be used. Hair conditioningagents in addition to the water-soluble film-forming polymer such asN-pantoyl-3-propanolamine (Panthenol) may also be included. Conventionalhair product additives such as vitamin E, jojoba oil, aloe extract,herbal extracts, and the like may also be included.

The remainder of the compositions of the present invention consistsessentially of solvent, at levels that can exceed 99% by weight. In mostinstances, the solvent will consist entirely of water. However, lowerviscosity products such as hair setting compositions for aerosol or pumpspray application may use an alcohol-water solvent combination.Therefore, compositions in accordance with the present invention mayoptionally contain up to about 90% by weight of a cosmeticallyacceptable alcohol, such as ethanol, isopropanol, and the like.

The hair thickening compositions of the present invention may also beprepared in the form of gels, creams, mousses, hair tonics, lotions,aerosols, pump sprays, dyes, hair conditioning products and coloringagents using conventional cosmetic product formulation techniques. Thiswould include the preparation of oil-in-water or water-in-oil emulsionsand microemulsions based upon the aqueous gelatin solutions of thepresent invention. The preparation of such emulsions and microemulsionsis essentially conventional and involves the combination of the aqueoussolutions of the present invention with an oil phase and a suitableemulsifier.

The hair thickening compositions of the present invention are preparedby first making a concentrated aqueous gelatin solution. The aqueousgelatin solution concentrate should contain up to about 30% by weight ofgelatin that is prepared by combining the gelatin with water at atemperature between about 100° F. and about 170° F. and preferably about140° F. The two ingredients are combined with mixing until the gelatinis completely dissolved. At this stage, pH is not critical andtherefore, the gelatin pH is not adjusted.

A separate solution of the water-soluble cosmetic film-forming polymeris prepared. Polymer and water are also combined with heating at atemperature between about 80° F. and about 150° F., and preferably atabout 120° F. Here, pH is important, but a broader range may be employedbecause long-term product stability is not a factor at this stage. Anythickening agent, preservative or other optional ingredient should bedissolved in the water before the film-forming polymer is added. Thefilm-forming polymer is added in increments, typically about 20 pounds.Each incremental quantity is mixed until completely dissolved, afterwhich the pH is checked, and acid neutralizing agent is added, ifneeded, in an amount sufficient to maintain the solution pH betweenabout 6.0 and about 9.5, and preferably, at this stage, between about6.0 and about 7.0 in order to maintain an easier to mix viscosity. Theincremental addition of polymer followed by pH measurement andadjustment is repeated until the amount of polymer to be added iscompletely dissolved and the polymer solution is at a pH within the 6.0to 9.5 range, and again, preferably between 6.0 and 7.0.

The gelatin concentrate is then added to the polymer solution, again inincremental quantities, typically 50 pounds at a time, so as not toshock the solution pH and precipitate the gelatin. Following eachincremental addition, the solution is stirred to dissolve the gelatinconcentrate in the aqueous polymer solution, after which pH is measuredand adjusted following the procedure utilized for the preparation of thepolymer solution. Incremental addition of gelatin concentrate followedby pH measurement and adjustment is repeated until the gelatinconcentrate is completely dissolved in the polymer solution within a pHrange of 6.0 to 9.5 and preferably between 6.7 and 7.0.

Any remaining ingredients are then added. A final quantity of acidneutralizing agent is added, if necessary, to bring the product within a6.5 to 8.5 pH range and now preferably between 6.9 and 7.5. A quantityof water is then added, calculated to bring the final product within thedesired batch volume. The product is then cooled and packaged byconventional techniques.

As can be readily appreciated, the compositions of the present inventioncan be prepared as concentrates suitable for dilution by distributors orthe ultimate consumer to obtain the hair thickening compositions of thepresent invention. Such concentrates are considered to be within thescope of the present invention and may be prepared by omitting all orpart of the final water addition step and even some of the water in thegelatin concentrate and polymer solution. Concentrates in accordancewith the present invention have a viscosity between about 4,000 andabout 400,000 cps. at room temperature and a polymer to gelatin ratiobetween about 3:10 and about 50:1.

A particularly preferred formulation is set forth below, listingpreferred ranges of ingredients and the optimum concentration inweight-percent for each:

    ______________________________________                                        INGREDIENT           RANGE    OPTIMUM                                         ______________________________________                                        PVP (45k Mw.sub.n)   0.1-15%  5.6%                                            250 bloom Type A gelatin                                                                           0.3-15%  1.3%                                            Cross-linked polyacrylic acid thickener                                                            0-5%     0.3%                                            Triethanol amine (99% aqueous                                                                      0-2%     0.5%                                            solution)                                                                     Methylparaben preservative                                                                         0-5%      0.25%                                          Perfume              0-5%      0.28%                                          Deionized water      q.s.     92.3%                                           ______________________________________                                    

The method of the present invention for increasing hair shaft thicknesstopically applies the hair thickening compositions of the presentinvention to the hair in an amount sufficient to impregnate the hair.Generally from about 2 to about 20 mL of the hair thickening compositionis applied to the hair, although longer hair may require significantlylarger quantities.

Consistent results are achieved when the compositions of the presentinvention are applied to moist towel-dried hair following shampooing.The hair thickening composition may be massaged into the hair, spreadevenly with comb or brush, set with rollers or blown dry with styling.Alternatively, it may be lightly sprayed on the surface of the hair, inwhich case it functions as a "setting" product. Daily, in-betweenshampooing, the hold may be reactivated without the addition of moreproduct by simply applying a mist of water and re-setting the hair aspreviously described. The hair thickening and setting compositions ofthe present invention are removed by washing the hair.

Compositions in accordance with the present invention provide at aminimum at least a 5-10% increase in hair shaft thickness, or diameter,up to about a 25% increase, and greater. The increase in hair shaftthickness has been continued by independent laboratory testing, as setforth in the examples below. The thickness increase is attributable tothe gelatin component of the composition, the consistent topicalapplication and combability of which would not be possible without thelevel of water-soluble cosmetic film-forming polymer employed. Thepresent invention provides a means by which aqueous solutions of gelatincan be prepared with elevated levels of film-forming polymer in order toprovide a suitable product for topical application to the hair.

The following non-limiting examples set forth hereinbelow illustratecertain aspects of the invention. All parts and percentages are byweight, unless otherwise noted.

EXAMPLES Example 1 Preparation of Hair Thickening Gel

A gel solution in accordance with the present invention was prepared byfirst dissolving 26 pounds of 250 bloom Type A gelatin (Hormel) in 330pounds of water in a heated mixer equipped with stirring blades. Thegelatin and water were mixed with heating to 140° F. until a uniformhomogeneous mixture was formed. The resulting mixture was maintained at140° F.

In a separate steam jacketed mixer with stirring blades, six pounds ofCARBOPOL 941 and five pounds of methylparaben (Mallincrodt) preservativewere combined with 1,500 pounds of water. The ingredients were mixedwith heating to 120° F. until a uniform homogeneous mixture was formed.The pH of a sample of the mixture was checked and determined to be 5.6.7 oz. TEA was added to bring the pH to 6.5.

112 pounds of LUVISCOL K-30, a PVP having a number-average molecularweight of 45,000 daltons, was added to this mixture in 20 poundincrements. Upon addition of the first 20 pounds of the PVP, theingredients were mixed with heating to 120° F. until the PVP wascompletely dissolved. The pH of a sample was checked and determined tobe 6.1. Because this was at the low end of the desired pH range, 7 oz.of a 99% aqueous solution of TEA (Union Carbide) was added with mixinguntil uniformly dispersed. The pH of a sample was checked again anddetermined to be 6.6. Because the pH was mid-range of the preferredinitial 6.0-7.0 pH range providing a lower, easier to mix viscosity, 20additional pounds of PVP was added to the mixture and stirred withheating to 120° F. until the PVP was completely dissolved. The procedureof adjusting the pH, adding more PVP and readjusting the pH was repeateduntil all 112 pounds of PVP was added to the mixture.

The amount of TEA that should be added to the mixture to adjust the pHis readily determined by one of ordinary skill in the art without undueexperimentation.

Once all the PVP is dissolved in solution, the previously preparedgelatin concentrate is then added in 50 pound increments, with the pH ofthe mixture being adjusted within a 6.7 to 7.0 range following eachincremental adjustment.

Thus, 50 pounds of the gelatin solution was added to the PVP solution.The ingredients were mixed with heating to 140° F. until uniformhomogeneous mixture was formed. The pH of a sample was checked anddetermined to be 6.5. Another 7.0 oz. of 99% aqueous TEA was added tothe mixture with stirring until uniformly dispersed. The pH of a samplewas then checked and determined to be 6.8.

Because the pH was within the range of 6.7 to 7.0, 50 more pounds of theconcentrated gelatin solution was added to the PVP-gelatin mixture thatwas stirred with heating to 140° F. The pH was checked again, and theTEA solution was added to the mixture to bring the pH back within therange of 6.7 to 7.0.

The procedure of adjusting the pH, adding more gelatin concentrate, andreadjusting the pH was repeated until all 356 pounds of the gelatinconcentrate was added to the mixture.

Water was added to bring the total batch size to 1,995 pounds. Themixture was stirred until uniform and a final pH measurement of a samplewas made. The pH was 6.7. The product was then cooled to roomtemperature with continuous mixing. At room temperature, five pounds ofperfume was added and stirred until uniform. A final addition of 4.5lbs. of TEA was made to bring the product pH to 7.2 and stirred untiluniform. The product was then packaged in 180 mL squeeze bottles usingautomated equipment.

PERFORMANCE EVALUATION

The material of Example 1 and three hair samples were sent to anindependent laboratory for evaluation. The laboratory described the hairsamples as follows:

Five strands of thin, light gray hair labeled "natural clean hair."

A taped bundle of about 100 strands of light grayish and brownish hairs,and several black hairs.

A taped bundle of about 100 strands of thin, straight, dark black hair.

The laboratory was unaware that the second sample of light grayish andbrownish hairs with several black hairs were synthetic, rather thannatural hairs.

The ends of three strands of the "natural clean hair" were tapedtogether. The loose strands of hair were washed for one minute using a1.6% solution of TWEEN® 20 in cold water. After washing, the hairs wererinsed under cold tap water for 30 seconds. After rinsing, the hairswere dried for about 60 seconds using a hot air blower at a distance of12-15 inches until the strands separated.

Sections of about 50 hairs were cut six to eight inches in length fromthe strands of hair from the other two samples. One end of each hairsection was taped, respectively. The loose strands of hair were washedfor one minute using a 1.6% solution of TWEEN® 20 in cold water. Afterwashing, the hairs were rinsed under cold tap water for 30 seconds.After rinsing, the hairs were dried for about 90 seconds using a hot airblower at a distance of 12-15 inches until the strands separated.

After drying, the widths of a number of hairs of all three samples weremeasured using the ocular scale of a Bausch & Lomb stereoscope at amagnification of 25×. The apparent widths of the hair samples werereported in mils (1 mil=0.001").

Loose ends of each sample were then wetted for 15 seconds under cold tapwater. After wetting, the hair thickening composition of Example 1 wasmassaged on each wet hair sample for 5-10 seconds, while gently removingthe excess gel with light finger pressure. Each treated hair sample wasdried using a hot air blower for several minutes. As the treated hairsamples dried, they tended to bond together and were stiffer. The bondedhair strands were separated by gently twisting the treated strands ofhair apart. After the treatment, the widths of a number of hairs of eachtreated hair sample were measured using the ocular scale of a Bausch &Lomb stereoscope at a magnification of 25×. The results are set forth inthe table below.

    ______________________________________                                        HAIR SAMPLES                                                                            "Natural Light Gray/                                                          Clean"   Brown      Black                                           ______________________________________                                        Before Treatment                                                              # Of Measurements                                                                         20         25         25                                          Average Width                                                                             2.5        3.8        2.8                                         Standard Deviation                                                                        0.7        0.6        0.4                                         After Treatment                                                               # Of Measurements                                                                         18         25         25                                          Average Width                                                                             3.1        3.8        3.4                                         Standard Deviation                                                                        0.5        0.9        0.6                                         ______________________________________                                    

Unknown to the laboratory, the hair samples that were natural hairmeasured significantly thicker in width after application of the hairthickening composition of Example 1. The synthetic hair sample did notincrease in width after application of the hair thickening composition.

Example 2 Preparation of Sprayable Hair Setting Product

8 oz. of SD40 alcohol (40% specially denatured ethanol in water) isadded to 8 oz. of the product of Example 1. The final composition waseasily sprayed from a conventional pump-spray device. The viscosity wasalso suitable for aerosol application.

The present invention thus provides a proven means by which an actualand significant increase in hair shaft thickness may be produced.Conveniently, the hair thickening compositions of the present inventioncan be prepared in the form of conventional hair care products, so thatthe hair thickening treatment method of the present invention can beadopted by an individual without significant changes in their daily haircare regimen.

The foregoing examples and description of the preferred embodimentshould be taken as illustrating, rather than limiting, the presentinvention as defined by the claims. As will be readily appreciated,numerous variations and combinations of the features set forth above canbe utilized without departing from the present invention as set forth inthe claims. All such modifications are intended to be included withinthe scope of the following claims.

What is claimed is:
 1. A hair thickening composition for topicalapplication comprising an aqueous solution of gelatin at a concentrationbetween about 0.30 and about 15% by weight, a water-soluble cosmeticfilm-forming polymer at a concentration greater than 60% that of saidgelatin and between about 0.10 and about 15% by weight, and an acidneutralizing agent to maintain said solution at a pH range between about6.0 and about 9.5, within which said gelatin and said film-formingpolymer are stable together at their respective concentrations.
 2. Thehair thickening composition of claim 1, wherein said pH is between about6.5 and about 8.5.
 3. The hair thickening composition of claim 2,wherein said pH is between about 6.9 and about 7.5.
 4. The hairthickening composition of claim 1, wherein said gelatin is selected fromthe group consisting of 50 to 300 bloom Type A pork skin gelatin and 50to 300 bloom Type B calf skin and bone gelatin.
 5. The hair thickeningcomposition of claim 4, wherein said gelatin is 250 bloom Type Agelatin.
 6. The hair thickening composition of claim 1, wherein saidcosmetic film-forming polymer is selected from the group consisting ofpolyvinyl acetate, hydrolyzed polyvinyl acetate, polyvinyl pyrrolidone,copolymers of vinyl acetate and polyvinyl pyrrolidone, polyvinylalcohol, acrylate-acrylamide copolymers, and acrylate-polyvinylpyrrolidone copolymers.
 7. The hair thickening composition of claim 6,wherein said cosmetic film-forming polymer is polyvinyl pyrrolidone. 8.The hair thickening composition of claim 1, wherein said aqueoussolution comprises up to about 90% by weight of ethanol or isopropanol.9. The thickening composition of claim 1, wherein said acid neutralizingagent is triethanol amine.
 10. The hair thickening composition of claim1, wherein said polymer concentration exceeds that of said gelatin.